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    <title>ShellCheck: SC2315 – In bats, `!` does not cause a test failure. Fold the `!` into the conditional!</title>
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    <h1>SC2315 – ShellCheck Wiki</h1>
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    <h2
id="in-bats--does-not-cause-a-test-failure-fold-the--into-the-conditional">In
bats, <code>!</code> does not cause a test failure. Fold the
<code>!</code> into the conditional!</h2>
<h3 id="problematic-code">Problematic code:</h3>
<div class="sourceCode" id="cb1"><pre class="sourceCode sh"><code class="sourceCode bash"><span id="cb1-1"><a href="SC2315.html#cb1-1" aria-hidden="true" tabindex="-1"></a><span class="co">#!/usr/bin/env bats</span></span>
<span id="cb1-2"><a href="SC2315.html#cb1-2" aria-hidden="true" tabindex="-1"></a></span>
<span id="cb1-3"><a href="SC2315.html#cb1-3" aria-hidden="true" tabindex="-1"></a><span class="ex">@test</span> <span class="st">&quot;test&quot;</span> {</span>
<span id="cb1-4"><a href="SC2315.html#cb1-4" aria-hidden="true" tabindex="-1"></a>    <span class="co"># ... code</span></span>
<span id="cb1-5"><a href="SC2315.html#cb1-5" aria-hidden="true" tabindex="-1"></a>    <span class="ot">! </span><span class="bu">[</span> <span class="va">$status</span> <span class="ot">==</span> 0 <span class="bu">]</span></span>
<span id="cb1-6"><a href="SC2315.html#cb1-6" aria-hidden="true" tabindex="-1"></a>    <span class="co"># ... more code</span></span>
<span id="cb1-7"><a href="SC2315.html#cb1-7" aria-hidden="true" tabindex="-1"></a><span class="er">}</span></span></code></pre></div>
<h3 id="correct-code">Correct code:</h3>
<div class="sourceCode" id="cb2"><pre class="sourceCode sh"><code class="sourceCode bash"><span id="cb2-1"><a href="SC2315.html#cb2-1" aria-hidden="true" tabindex="-1"></a><span class="co">#!/usr/bin/env bats</span></span>
<span id="cb2-2"><a href="SC2315.html#cb2-2" aria-hidden="true" tabindex="-1"></a></span>
<span id="cb2-3"><a href="SC2315.html#cb2-3" aria-hidden="true" tabindex="-1"></a><span class="ex">@test</span> <span class="st">&quot;test&quot;</span> {</span>
<span id="cb2-4"><a href="SC2315.html#cb2-4" aria-hidden="true" tabindex="-1"></a>    <span class="co"># ... code</span></span>
<span id="cb2-5"><a href="SC2315.html#cb2-5" aria-hidden="true" tabindex="-1"></a>    <span class="bu">[</span> <span class="va">$status</span> <span class="ot">!=</span> 0 <span class="bu">]</span></span>
<span id="cb2-6"><a href="SC2315.html#cb2-6" aria-hidden="true" tabindex="-1"></a>    <span class="co"># ... more code</span></span>
<span id="cb2-7"><a href="SC2315.html#cb2-7" aria-hidden="true" tabindex="-1"></a><span class="er">}</span></span></code></pre></div>
<h3 id="rationale">Rationale:</h3>
<p>Bats uses <code>set -e</code> and <code>trap ERR</code> to catch test
failures as early as possible. Although the return code of a
<code>!</code> negated command is inverted, they will never trigger
<code>errexit</code>, due to a bash design decision (see <a
href="SC2315.html#related-resources">Related Resources</a>). This means that tests
which use <code>!</code> can never fail.</p>
<h3 id="exceptions">Exceptions:</h3>
<p>The return code of the last command in the test will be the exit code
of the test function. This means that you can use
<code>! &lt;command&gt;</code> on the last line of the test and it will
still fail appropriately. However, you are encouraged to still transform
the code in this case for consistency.</p>
<h3 id="related-resources">Related resources:</h3>
<ul>
<li><p><a href="SC2314.html">SC2314: In bats, ! does not cause a test failure
(for non-conditionals)</a></p></li>
<li><p><a href="https://www.shellcheck.net/wiki/SC2251.md">SC2251: This ! is not on a condition and
skips errexit</a></p></li>
<li><p><a
href="https://stackoverflow.com/a/39582012/760746">Stackoverflow: Why do
I need parenthesis In bash <code>set -e</code> and negated return
code</a></p></li>
<li><p><a href="https://linux.die.net/man/1/bash">bash manpage</a> (look
at <code>trap [-lp] [[arg] sigspec ...]</code>):</p>
<blockquote>
<p>The ERR trap is not executed [...] if the command's return value is
being inverted via !</p>
</blockquote></li>
</ul>
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